Exhaust manifold problem - can any one help urgently

[Marina Bay]

Hi guys,

I have MErcruiser 5.7L 1999just now rebuilt by my freind but I'm having a problem with left hand side manifold that it does not exhaust out any smoke, the other side is working fine, I made a test try the engine temperature was good not overheat noticed at all but only the left side manifold part I felt it is getting heat fast as nothing is coming exhausted out. Can any body tells me what I have to check first?

I think that there is something is blocking the smoke to get out.

Thank you

 

[CHARGER2]

Re: Exhaust manifold problem - can any one help urgently

If that bank is firing at all, smoke is coming out somewhere... blocked exhaust will stall the engine.

Did you run it without the exhaust piping to the outdrive? How do you know no smoke is coming out?

 

[Marina Bay]

Re: Exhaust manifold problem - can any one help urgently

The engine was not stall at all, I only realized that there is somthing wrong with the manifold that it came very hot on the left hand side only, water circulation was good.

I did not run it without the piping.

 

[Don S]

Re: Exhaust manifold problem - can any one help urgently

The engine was not stall at all, I only realized that there is somthing wrong with the manifold that it came very hot on the left hand side only, water circulation was good.

I did not run it without the piping.

That means the exhaust from the engine is going out of it (that's why it's hot) your problem is you don't have water circulating through and out of it. (also why it's hot).

Could be because the water passages are plugged up, or being it's just been rebuilt, something is not installed properly.

Need the Mercruiser serial number for your engine it will be in the form of a 0 then a letter, followed by 6 numbers.

Is your engine fresh water cooled, or raw water cooled?

 

[Marina Bay]

Re: Exhaust manifold problem - can any one help urgently

My engine serial number is 0L358898.

It is a salewater cooling as to my knowledge.

 

[Don S]

Re: Exhaust manifold problem - can any one help urgently

My engine serial number is 0L358898.

It is a salewater cooling as to my knowledge.

Assuming you mean Saltwater cooling, I would pull the exhaust elbows and check the water passages to see if they are open. Especially where the water exits from the elbow.

 

[series60]

Re: Exhaust manifold problem - can any one help urgently

One of the biggest culprits with manifolds getting hot is blocked water passages. The elbow is where water and hot exhaust join and exit to the Y-pipe. Saltwater operation and crud buildup can block this area fairly easily. Check the image to see what I am talking about.

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